Update sample Storefront API version

Author: tiagocandido

platforms/android/samples/MobileBuyIntegration/README.md

@@ -77,7 +77,7 @@ Edit `.env`:
 ```text
 STOREFRONT_DOMAIN=your-store.myshopify.com
 STOREFRONT_ACCESS_TOKEN=your-token
-API_VERSION=2025-07
+API_VERSION=2026-04
 ```
 
 Optional values enable Customer Account API and buyer identity demo flows:

platforms/android/samples/MobileBuyIntegration/app/build.gradle

@@ -23,7 +23,7 @@ def properties = loadProperties()
 // Storefront API
 def storefrontDomain = properties.getProperty("STOREFRONT_DOMAIN")
 def accessToken = properties.getProperty("STOREFRONT_ACCESS_TOKEN")
-def apiVersion = properties.getProperty("API_VERSION", "2025-07")
+def apiVersion = properties.getProperty("API_VERSION", "2026-04")
 
 // Customer Account API
 def customerAccountApiClientId = properties.getProperty("CUSTOMER_ACCOUNT_API_CLIENT_ID")

platforms/android/samples/MobileBuyIntegration/app/src/main/graphql/schema.graphqls

@@ -24,7 +24,7 @@ npx -y dotenv-cli -e .env -- sh -c '
   fi
   if [ -z "$VERSION" ]; then
     echo "❌ API_VERSION is not set. Check your .env file."
-    echo "   Add API_VERSION=2025-07 to your .env"
+    echo "   Add API_VERSION=2026-04 to your .env"
     exit 1
   fi